Covering Chicago's struggles with the rain starts, ends with history

Work continues last month at the Deep Tunnel reservoir in south suburban Thornton. The reservoir, a converted quarry, is scheduled to be completed in 2015, but some officials say it may not be enough to solve the region's flooding problems during heavy rains.

For a city built on a swamp, dealing with rainstorms has always been a problem.

More than a century ago, Chicago infamously engineered its namesake river to flow backward, away from Lake Michigan. The dredging of canals and construction of locks and sluice gates separated the waste of a growing metropolis from its source of drinking water. But if it rained enough, officials were forced to open the locks and gates and allow fetid, debris-strewn water to flush out into Lake Michigan.

By the early 1970s, flooding and sewage overflows into the lake happened so frequently that local officials decided to embark on another big engineering project, the Deep Tunnel, a network of giant underground stormwater tunnels and cavernous reservoirs they vowed would “bottle up rainstorms” in Chicago and suburban Cook County. But the $3 billion project still isn’t completed, and officials increasingly fear that a system designed more than three decades ago won’t be able to handle the fast, intense storms that climate scientists project will hit Chicago more frequently in the not-so-distant future.

The Tribune reported in 2011 that the region’s aging sewers and completed portions of the Deep Tunnel frequently are overwhelmed even by moderate rainstorms.

And Lake Michigan has been hit harder by waste water during the past five years than it was during the previous 25 combined, according to the Metropolitan Water Reclamation District, the independent, tax-supported agency that oversees the Deep Tunnel.

In April, a big storm forced nearly 11 billion gallons of murky, bacteria-laden water into the lake, the biggest surge of sewage and runoff since 1985.

Starting with former Mayor Richard Daley, Chicago officially is a proponent of small, neighborhood projects intended to keep runoff from reaching the sewers in the first place.

Mayor Rahm Emanuel embraced “green infrastructure” last year and unveiled a plan he said would make Chicago a national leader. But other than a few pilot projects, the Tribune found that the city has been slow to follow through on more than a decade of promises.

“These things already are being done in bits and pieces around the country,” said Karen Hobbs, a senior water analyst for the nonprofit Natural Resources Defense Council who formerly worked as a top official in the now-defunct Chicago Department of Environment. “But we still need to change our mindset about how we spend our limited budget for infrastructure investments.”